The last freeware version from disktrix is what I use. the GUI is not one of the nicest...but I let it do its work at night when I go to sleep anyway.
What I like from this one is that it first defrags files and moves them afterwards to the inner or outer part of the harddisk c.q. partition depending on the setting that you prefer. In my case the files I used most are put on the outer part, improving the access speed.
Since I tried this one, I dropped all the others.
Oh yeah...what I also like a lot from this is that it doesn't keep b.tching about lack of space on the harddisk/partition, while others start complaining that 10%-15% has to be free on the harddisk/partition before commencing or don't start at all before this 'requirement' is met.
What is that about anyway? (that there is a need to have free room is logical to me, but why put the percentage behind the number? To me the fact that 10 Gbyte of free space should be more than enough on a 500 Gbyte harddisk....but no, it has to be 50 Gbyte? What can be so big?